The present invention relates to a connecting arrangement and, more particularly, to a connecting arrangement for horizontal scaffolding supports in scaffolding with vertical supports disposed at intervals corresponding to a grid system and including horizontal perforated disks.
Scaffolding of the aforementioned type generally includes a perforated disk on a support plate, with the perforated disk including holes into which the connecting heads of the scaffolding elements, serving as support structure, can be inserted with inserted wedges. The heads are generally designed to merge in wedge-like fashion by vertical side faces thereof and generally have, approximately at a horizontal center thereof, a disk slot for mounting on the perforated disks, as well as being provided in their upper and lower supporting parts with vertically continuous wedge openings.
Connecting structures for scaffolding elements have many different shapes designed to fit specific scaffolding systems and, for example, a connecting structure for scaffolding elements is proposed in Offenlengungsschrift No. 27 24 932.
In view of the great weight of steel components and the need to be able to erect and take down non-flammable scaffolding rapidly and easily even in constricted spaces, scaffolding made of lightweight material has been developed in many forms; however, the forces to be accommodated and supported at the connecting nodes of the scaffolding are so great that connecting heads made of steel have been used almost exclusively, with the connecting heads being linked to the scaffolding elements such as tubing and U-shaped beams by either pressed or shaped connections or by welded connections with the scaffolding elements.
As a result of the forces which must be taken into consideration, even light-metal tubes have developed considerable accumulations of weight at their ends making such light-metal tubes awkward to handle. Moreover, different materials with different properties always pose problems and, while the U-shaped span members have so far always been made of steel, it is desirable to have light-metal parts used throughout a light-metal scaffolding.
The aim underlying the present invention essentially resides in providing, for a span member made of a light metal, a connecting head of light metal which is capable of accepting and transmitting, under optimum conditions and forces that develop, has a suitable construction, is space and material saving, and which permits the connecting head to be welded to the light metal of the U-shaped beam with no adverse effects on the U-shaped beam if possible.
In accordance with the present invention, a connecting head is provided which is fashioned of the cast light metal and is constructed for a connecting area that is suitable for welding and fits a U-shaped beam of a span member, made of a light metal that a top thereof. An inwardly projecting welding flap is provided on the connecting head and is adapted to abut each wall of the U-shaped beam. A weld seam edge of the flap lies parallel beneath the supporting edge web and is reinforced and inwardly beveled at the bottom of the U-shaped beam. A head area abutting a lower horizontal web of the U-shaped beam includes a welding aid web extending into an interior of the U-shaped beam. A disk slot is tapered in an area of an inner base to a thickness of the disk, and shaped structures formed by depressions on the outer surfaces of the head include reinforcing edge areas adjacent to the wedge openings.
With U-shaped beams made of steel and steel heads, which, in practice, are welded to flaps as well, it is not important to be precise about an optimum design or construction of all areas of the head because the strength values of steel are considerably higher than that of light metal. Thus, in steel scaffolding constructions the welded seams can be arranged differently.
The present invention provides a construction for a light-metal in which the U-shaped beam includes an inwardly reinforced support edge web, on which hook-shaped suspension talons or clips of the scaffold platform can be used many times over a considerable number of years without resulting in any excessive wear. With the construction of the present invention, installation dimensions do not have to be changed from the corresponding dimensions in steel. Moreover, the inner lower edge of the supporting edge web along the upper edge area of the corresponding welding flap is constructed so that a receiving space is formed in which a suitable welded seam can be placed. More particularly, the space is formed so that a V-shaped seam can be placed thereat.
While the length of the welded flap depends upon the strength requirements and can be determined by a skilled artisan in the usual manner, while short flaps with vertical walls and edge walls are conventional in steel, a seam extending parallel to the supporting edge is provided in accordance with the present invention which allows more favorable acceptance of forces and is better suited to the requirements of light metal.
Moreover, consideration can also be given to the fact that the strength values of the light metal are reduced by a welding operation. In this situation, there is a relatively great distance to the supporting edge and the greatest weakening occurs at a certain distance from a maximum stress on the light metal so that a proper balance has been found. Otherwise, the head is welded only on the outside of the light-metal U-shaped beam.
Furthermore, by virtue of the features of the present invention, there is adequate support and accumulated material for suitable welding in a vicinity of the welding flaps. In a lower area of the connecting head, which abuts the horizontal web, no welded connection is provided on the inside thereby greatly simplifying manufacturing.
Additionally, due to the support of liquefied material during a welding from the outside, a formation of a so-called welding pool results and the present invention provides a welding aid web in the lower edge area at the head extending into an inner area of the U-shaped beam thereby offering optimum welding conditions thereat.
Additionally, with the subject matter of the present invention, the shape of the head is altered with respect to a similar head made of steel so that the outer area of the disk slot is made with a large amount of play, for example, several mm, that is usual for such scaffolding, so that the connecting heads will fit on properly, but the disk slot is made to taper in a direction toward the inner bottom portion thereof so that essentially it only has a very small amount of play, for example, for all practical purposes, equal to the thickness of the disk. This arrangement makes it possible for a greater accumulation of material in an area of maximum forces in the connecting head than in steel connecting heads of the same basic type thereby reducing the stress.
Additionally, according to the present invention, edge areas as well as the wedge openings, high stresses, and lower material strengths relative to steel are better adapted by the construction of the present invention and thus, with external dimensions in a top view for the connecting head made of steel, a horizontal support is created with a light-metal connecting head whose realization was not previously realized for lack of a suitable construction.
The favorable construction or arrangement of the present invention for welding light-metal parts makes it possible to do without any steel connecting head whose fastening for a light-metal U-shaped beam is possible only with a correspondingly large and long engaging portions and end areas of the span member. The provision of large and long engaging portions or fastening parts would block the space in which the talons or claws of ordinary scaffold platforms engage.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings, which show, for the purposes of illustration only, several embodiments in accordance with the present invention.